They’re prehistoric, alien-looking creatures that capture children’s attention at aquarium touch tanks and swarm the Garden State bays at each summer’s outset.
They’re horseshoe crabs — and now they’re more important than ever.
The animals are critical to the work of pharmaceutical companies, especially during this pivotal mass distribution of the coronavirus vaccine. The crabs’ milky blue blood has been used for decades to detect harmful pathogens in medicines, allowing drugmakers to ensure their products are pure before being shipped out and injected into human arms.
But harvesting the skeletal sea-dwellers isn’t without consequences, especially along the Delaware Bayshore in South Jersey where a long-fought battle between industry and conservation groups rages on.
Few earthly creatures predate the horseshoe crab. The animals, which are not true crabs but more closely related to spiders and scorpions, have remained largely unchanged for 350 million years. Their appearance, an exoskeleton defined by a massive domed head and long pointed tail, is unmistakable.
The world’s largest population of horseshoe crabs uses the Delaware Bay as a spawning ground, according to the Atlantic States Marine Fisheries Commission. Every year in May and June, thousands of the crabs come ashore along the bay to mate. Each female crab can lay up to 90,000 eggs on the beach.
Those eggs make the crabs a keystone species for the bay’s ecosystem, serving as a smorgasbord for hungry fish and shorebirds.
Favorite feeders include a threatened species of shorebird call red knots, which use Delaware Bay as a critical rest stop on their annual migration from the Arctic Circle to Tierra del Fuego on the southern tip of Argentina. The eggs, full of fats and proteins, are a critical food source for the birds.
Larry Niles, a biologist who has studied the Delaware Bay ecosystem since the 1980s, said his research indicates the number of horseshoe crabs in bay essentially determines the populations of red knots.
“Without that fat, they’ll either die on the way, they’ll die when they get there, or they won’t reproduce,” said Niles, who first worked with New Jersey Department of Environmental Protection and now helps conservations groups.
The importance of a healthy horseshoe crab population goes beyond red knots, according to Niles. He stresses the crabs, and their eggs, support the bay’s fish populations as well. It’s an ecosystem that he argues has been long undervalued by state and federal regulators.
“This isn’t just about the birds,” Niles said. “This is about the productivity of the Delaware Bay system.”
Horseshoe crabs have long been harvested for human use. In the 1800s and early 1900s, the crabs were turned into fertilizer and livestock feed used by farms, according to the ASMFC. Horseshoe crab harvests in the Atlantic largely vanished in the mid-1900s after the sea creatures fell out of demand for fertilizer, but returned in the ’90s when they became prized bait for eel and whelk fisheries.
But for most people, horseshoe crabs serve a more practical purpose: Their blood is used to ensure our medicine is safe.
Horseshoe crab blood is the main ingredient in limulus amebocyte lysate (LAL), a compound used by pharmaceutical companies to test drugs for purity, ensuring that bacteria and other pathogens are not tainting the medicine. The crabs’ blood reacts and clots when it encounters harmful endotoxins found in some bacteria, like E. Coli.
“It works really well, it’s extremely accurate and it’s fairly inexpensive.” said Brett Hoffmeister, who heads the horseshoe crab program for the Massachusetts company Associates of Cape Cod, Inc. “This has been the gold standard since the 70s.”
To get that blood, LAL manufacturers like ACCI catch and bleed the crabs, then return the animals to the wild. Hoffmeister said each company operates a little differently, but generally the crabs spend about 24 hours out of their natural habitat for the process.
The ASMFC estimates about 15% of horseshoe crabs that are bled die after the process, though some research has found mortality rates upward of 30%.
Today, the DEP permits just one company — Limuli Labs in Cape May — to take horseshoe crabs from state waters. The business is required to report how many crabs it harvests annually to the state but that information is protected as confidential, according to DEP spokeswoman Caryn Shinske.
Limuli Labs did not respond to requests for comment from NJ Advance Media. Limuli and ACCI are two of just five companies that harvest and bleed crabs along the Atlantic Coast.
Hoffmeister said the biomedical industry has not seen increased demand during the pandemic, though overall demand for LAL testing has steadily increased over the past two decades as the biomedical industry has grown.
“Before COVID even showed its face, we were manufacturing product that is now being used to test these vaccines,” Hoffmeister said.
Caitlin Starks, the ASMFC’s fishery management plan coordinator for horseshoe crabs, said the commission won’t have data for the 2020 crab harvest until July, so it’s too early for regulators to say if the pandemic has driven demand higher.
Intense, unregulated fishing for horseshoe crabs shocked the Delaware Bay ecosystem in the 1990s, as the crabs became highly sought after as bait.
“That stress was so large in the ’90s that it just crashed the populations of horseshoe crabs,” said Tim Dillingham, the executive director of the Highlands-based American Littoral Society.
As the crabs’ population declined in the ’90s, so did the numbers of red knots. Weakfish numbers plummeted in the early 2000s as well, according to the ASMFC, something Niles argues is an effect of the crabs’s woes.
The ASMFC began regulating horseshoe crabs in 1998, in response to the fishing surge, and created limits on how many crabs can be taken from the Atlantic along the entire East Coast. Since 2013, the commission has set an annual limit of 500,000 male horseshoe crabs and zero female crabs for the Delaware Bay population.
The regulations include a mortality threshold of 57,000 horseshoe crabs for the biomedical industry, meaning if more than that sum of crabs die in a given year due to the bleeding operations, regulators are required to consider if stricter rules are needed.
That threshold has been surpassed in 12 of the past 13 years. But each time, the ASMFC has declined to put tighter rules on the biomedical harvesters.
“The thinking is that that level of biomedical mortality is so small that it’s not likely to have any negative impact,” Starks said.
New Jersey went a step further in 2008, enacting a moratorium on harvesting horseshoe crabs from Garden State waters. That measure shut down operations that collected the crabs for bait, but it included a loophole that allows crabs to be collected and bled for biomedical purposes, in turn allowing Limuli Labs to operate in Cape May.
Hoffmeister said he feels LAL manufacturers like his company have been unfairly blamed as a threat to the horseshoe crab stock and red knot numbers. Hoffmeister points to the fact that far more crabs are harvested for bait rather than bleeding, and that most bled crabs are returned to the ocean alive.
“The crabs are not going to go extinct because of it. The birds aren’t going to go extinct because of it,” Hoffmeister said of LAL testing. “This is something that we should be celebrating.”
The bait harvest restrictions have been effective in stabilizing the crab population, but the numbers in Delaware Bay have not been growing. In 2019, the ASMFC determined the bay’s horseshoe crab stock to be “neutral” compared to 1998 numbers, rather than “good” or “poor.”
Given the current state of the stock, conservation groups argue the biomedical operations deserve more scrutiny.
“The bait harvest is absolutely the largest stressor on the populations, but the biomedical industry contributes to it,” Dillingham said. “When you’re in a crisis situation, and you’re facing the extinction of birds, no one gets a pass.”
Conservationists like Dillingham and Niles urged a holistic approach to protecting the crabs.
“If we want to save the red knots, we probably need to remove all these stresses on the horseshoe crab population and aid them in boosting the populations back up,” Dillingham said.
That means stricter rules for bait harvests and crab bleeding, as well as investments to protect crab spawning beaches from damage done by climate change through rising sea levels and more intense storms.
Science may have already found the key to wean the pharmaceutical industry off crab blood.
A synthetic replacement for horseshoe crab blood, a new test called recombinant Factor C (rFC), is taking hold in Europe. The U.S. has not yet matched Europe’s embrace of rFC, but that could be coming soon as federal regulators seek to harmonize the nation’s rules with Europe and Japan.
One U.S. drugmaker, Indiana-based Eli Lilly, has already committed to using rFC for any new products it develops in-house. That includes an antibody cocktail treatment for COVID-19, according to Jay Bolden, a biologist who studies rFC for the company.
Bolden said his research and work done by others has found rFC to be just as good, if not arguably better, than LAL at detecting endotoxins.
Bolden said the plight of the red knots was the main factor in Eli Lilly’s push towards rFC. Instead, the company is making the move for performance, ethics and cost considerations.
Helping the birds would be a bonus, one that Bolden — a birder himself — understands well.
“We’re moving to rFC as a company for a lot of good reasons, but certainly we can appreciate the impact,” Bolden said.
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Michael Sol Warren may be reached at mwarren@njadvancemedia.com.
The Link LonkJanuary 31, 2021 at 06:46PM
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N.J.’s horseshoe crabs are vital to vaccine rollout. A battle for their survival rages on. - NJ.com
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